In this project, we study machine learning-based interference management algorithms for interference management in ultra dense network in pursuit of increasing the system throughput while maintaining the signal overhead feasible.

In this project, we study and develop a communication/network system for active mobile trackers working without any extra power source. In the mother project, fundamental technologies underpinning a self-powered miniature nationwide mobile position tracker system are developed. As the third sub-project, we develop wide area sensor communication network systems to support the active trackers.

Myeung Un Kim’s paper, “Min-SINR Maximization with DL SWIPT and UL WPCN in Multi-Antenna Interference Networks,” has been accepted for publication from IEEE Wireless Communications Letters (SCIE, 51/598 of Control and Systems Engineering in SJR Ranking). See here for details.

AiSLab including all the students visited G. Fettweis‘ group (Vodafone Chair/5G Lab) at TU Dresden on Jan. 2016. We gave a talk about “GFDM and GFDMA for 5G” and they gave a talk introducing their lab and their recent results. After a long discussion, the two groups found themselves at the same page for possible collaboration on GFDM research.

The 1st IITP-UNIST Low-Latency Network Workshop was successfully held in E208 at engineering building, UNIST with about 20 participants.
To make this workshop happen, CP (Creative Planner) Yongjae Lim from IITP kindly visited UNIST for the first time and made a presentation on the ICT R&D strategy of Korea.
5 professors (listed on the right-hand side) shared their current progresses on enabling the low-latency network from its architecting to its new protocol designs.
Active discussions with the valuable comments from CP Lim, which were right on the mark made the vision of UNIST toward the low-latency network clearer.

At June. 30, the NI technical seminar & practice were held in UNIST. The Software Defined Radios (SDN) is have emerged as a viable prototyping option for next generation wireless research.
After introducing about NI SDN, the practice was proceeded using LabVIEW comms/ Universal Software Radio Peripheral (USRP) reconfigurable I/O(RIO) system. The main activities were focused on understanding algorithm for Field-programmable gate array (FPGA), algorithm design and testing with NI hardware and software like the NI USRP RIO.

[From left: Kyunghan Lee, Hyun Jong Yang, Hyoil Kim, Changhee Joo]
5G mobile will be here by 2020. Remote surgery, cloud streaming gaming, drones, and robots will be all envisioned in 5G to bring better access and life-changing futuristic services to many. 5G will support 1,000-fold gain in capacity, hyper-connections for billion devices, and a 10Gb/s individual user experience capable of extremely low latency and response time. In particular, the demand for real-time immersive applications such as mission-critical remote control, remote robotic surgery, and interactive cloud gaming service is rapidly increasing. Current communication and network technologies, however, have their innate limits on the latency, which is way-beyond the requirement of immersive applications.

The UNIST research team, composed of Changhee Joo, Hyoil Kim, Kyunghan Lee, and Hyun Jong Yang, took a first step toward near-zero end-to-end latency, which propels us to commercialization of 5G, by starting a five-year research project “Research on Near-Zero Latency Network for 5G Immersive Service,” funded by the ministry of ICT and future planning, as of May 2015.

[End-to-end delay breakdown]

For the first time in the world, the UNIST team will shed light on issues in every network hop of the end-to-end network, as shown in the figure above, to achieve a few milliseconds of the total latency.

“Overhearing at users can increase the total data rate in two-way relay networks”
Chunguo Li (Southeast Univ.), Hyun Jong Yang (UNIST), Fan Sun (Stanford Univ.), John M. Cioffi (Stanford Univ.), and Luxi Yang (Southeast Univ.) got acceptance for the paper ” Multi-User Overhearing for Cooperative Two-Way Multi-Antenna Relays” in IEEE Transactions on Vehicular Technology (IF: 2.642) on June 2015. In this study, they showed that the data rate of the two-way relay network can be improved by allowing one user to overhear the signal transmitted by the other user. In particular, multiple relays equipped with multiple antennas are considered to further enhance the performance, which constitutes a cooperative multi-antenna relay network. Precoding matrices at the relays are derived in pursuit of minimizing the weighted mean square error. Simulation results show that the proposed scheme shows not only lower MSE but also higher achievable sum-rate than existing cooperative relaying schemes.

[Figure: Underwater Acoustic Communication, *WHOI.edu]
The Shallow-water Acoustic Variability Experiment 2015 (SAVEX15) is a joint underwater communication measurement campaign led by University of California San Diego and Korea Research Institute of Ships & Ocean Engineering (KRISO). The measurement will be conducted in shallow water (100m deep) in the Northern East Sea, ~100km southwest of Jeju Island, South Korea, over the period 14-29 May, 2015. The goal of SAVEX15 is to obtain acoustic and environmental data appropriate for studying the couple of oceanography, acoustics, and underwater communications in the Northern East Sea.
The AiSLab aided the KRISO in designing measurement scenarios and generating transmit signals for several promising technologies, which are cutting-edge state-of-the-arts even in the ground communication, such as orthogonal frequency division multiple-access (OFDMA), multi-directional relaying, multi-user MIMO (MU-MIMO), and generalized FDMA (GFDMA).
The application of underwater communication ranges from surveillance to resource mining, e.g., storing liquid carbon dioxide, mining methane hydrate, underwater monitoring (military defense, tsunami, earthquake), and etc [Figure]. The design of underwater communication, however, is challenging compared to the ground communication due to highly limited bandwidth (sonar radio), long distances but slow propagation, multi-hop relay network, significant time delay, time-varying frequency offset/Doppler shifts, and so on. Therefore, a careful consideration of these difficulties should be taken in designing transceivers. From this measurement campaign, the AiSLab and KRISO will look into the feasibility of the aforementioned techniques, which are carefully tailored for the underwater environment, and will pursue possible performance improvement.

[Figure: Cooperative Intelligent Transport Systems (C-ITS), *한국지능형교통체계협회]
The AiSLab hosted Hyundai Autoever and gave a talk about “Next Generation Wireless Access in Vehicular Environment (WAVE)” on Apr. 28, 2015. The AiSLab group presented a brief summary on the conventional WAVE technologies including IEEE 802.11p and V2X in 3GPP, and overview of the ongoing research projects in the US and Europe. In particular, PHY/MAC details of 802.11p were covered and several potential but critical technical issues that may happen in a very dense future vehicular network were addressed. The AiSLab then shared group’s technical vision towards the future Cooperative Intelligent Transport Systems (C-ITS) [Figure], which is the Korea version of the next generation vehicular network being envisioned by the Korea government. In this future network, possible services include not only the broadcasting services regarding public safety or emergency information, but also the two-way transactions such as tolling and internet access. The Hyundai Autoever, the research institute in the Hyundai group studying the infrastructure of the C-ITS, also shared their long-term vision on this project.

From Apr. 15 to 17, the 25th Joint Conference on Communications and Information (JCCI) was held in Buyeo, Korea. Prof. Hyun Jong Yang and Hyunmyung Oh were invited to give a special talk “5G Multiple-Access: Latency vs. Spectral Efficiency.” In this talk, a new mega trend in the mobile communication toward ultra-low latency was introduced with future killer applications. To achieve the ultimate goal of less than 10ms of the end-to-end latency, problems of the current multiple-access technologies were addressed. In particular, one of the promising multiple-access technologies achieving very low latency, the generalized frequency division multiple-access (GFDMA), is analyzed in two aspects: latency and spectral efficiency. Preliminary results showed that there exists a trade-off between the two aspects.

Researchers from one of the core research groups in ETRI (Electronics and Telecommunications Research Institute, Daejeon, Korea) visited UNIST on Apr. 10, 2015, to discuss the research project on small cell interference reduction for next generation communication. In this meeting, prof. Yang presented a comprehensive review on past year’s achievements and proposed a research plan for the second year.

In the precedent project, AiSLab and ETRI achieved 20% enhancement of the system throughput by reducing inter-cell interference in a dense small cell environment. In the successive year, it is expected to achieve 30% higher throughput compared to the previous year, and to study interference management algorithms for further interference mitigation under realistic constraints.